What "won" the south

The North Anti-South efforts ie: resource cutoffs, tariffs and black freedom propaganda.

Explanation:

If you are referring to the American Civil war the south was defeated by major resource cut-offs to the Confederate army, making them weak and causing mass desertion. Included in that were mass propaganda for black slaves from the north "better lives and pay" this caused mass revolts in southern plantations, finally the North imposed heavy tariffs on the South. Northern allies followed suit with the tariffs and put the final nail in the coffin of the dying confederate army.